It is vital that people are reminded that injured troops need to be taken care of as the Afghanistan conflict winds down, Prince Harry has said.

The prince was speaking in Trafalgar Square alongside a team of wounded servicemen and women he will be joining on a charity trek to the South Pole.

The group are due to fly to Cape Town, in South Africa, on Sunday. Two days later, they fly on to Antarctica.

The prince said the group would achieve something "quite remarkable".

Sub-zero training

He told the Walking with the Wounded departure event the expedition will prove "even when you've lost a leg or lost an arm, or whatever the illness may be, that you can achieve pretty much anything if you put your mind to it".

"The cause is for one cause and one cause only and that is to raise awareness for all the wounded, sick and injured whether it's in military life or whether it's in civilian life," the prince said.

By Sarah CampbellRoyal correspondent, BBC News

A chilly Trafalgar Square for Prince Harry was nothing compared to the -45 degree temperatures he will shortly be experiencing.

The media from across the world had gathered (the benefit of getting a royal involved) as had more than a few young girls who screamed "Harry come here" from the crowd each time they caught a glimpse of the prince.

Wearing the same as the rest of those taking part - a black fleece and black polar trousers - he took to the stage and was presented with the expedition flag.

He said how much the men and women he will be walking with had done just to get here.

This is clearly a cause very personal to him, not least having himself served in Afghanistan. The money raised will go towards helping wounded service personnel.

He added: "This trip is another way of reminding everybody that as Afghanistan draws down and these guys aren't in the news anymore so than they already are, it's a reminder to everybody that support must continue."

The group will spend time acclimatising to the extreme cold and altitude before walking 208 miles (335km).

As part of his expedition training, Prince Harry, an Army pilot who has served in Afghanistan, spent a night in a sub-zero Army test facility in September.

He and four team-mates, who all lost limbs in Afghanistan, were subjected to ambient temperatures down to -35C (-31F) and wind speeds of 45mph (72kph).

In the Antarctic, the team will face even lower temperatures of -45C (-49) and savage 50mph (80kph) winds.

They expect to trek for between nine and 12 miles a day (15 to 20km), dragging 11-stone (70kg) sledges, and are likely to encounter vast crevasses, moving ice-shelves, glaciers and snow storms.

Of the location, the prince said: "Antarctica is the only place on earth that is still as it should be. May we never tame that, but I can assure you the boys and girls behind me will do their very best."

The aim is to beat teams from the US and the Commonwealth to the southernmost point on the globe.

Image caption
Training has included a bitterly cold night in a sub-zero Army test facility, which simulated Antarctic conditions

The actual race begins on 30 November and competitors are expecting to reach the geographic South Pole by 16 December.

Prince's military training

Each team will have a guide and mentor, and they will all be followed by a support team in case of emergencies.

The expedition aims to highlight the courage of men and women injured while serving their country.

Walking with the Wounded, which has Prince Harry as patron, raises funds to re-train injured or sick service personnel to help them find another career.

Previously, one of Harry's team-mates - Major Kate Philp, from Knightwick in Worcestershire, who lost a leg on active service - said the prince's Army background made him a good team-mate.

"He knows what he's doing. He's got his military training... so he's a good extra pair of hands," she said.

Harry's other team-mates are Sgt Duncan Slater, from Muir of Ord in Scotland, who lost both his legs in a blast in Afghanistan in 2009; Capt Guy Disney, from Oxford, who lost his right leg in a rocket attack in 2009 and Capt Ibrar Ali, from York, who lost his right arm in a roadside bomb in 2007.

In 2011, Harry took part in a Walking with the Wounded fund-raising expedition to the North Pole, but withdrew early to attend his brother's wedding.

He did not take part in last year's failed bid to conquer Mount Everest because of his military commitments.